This invention relates to a vehicle seat having a seat frame and a backrest frame which, in particular, is made of a light metal diecast material and which has two backrest side members which extend in parallel to one another and are constructed as profiles open to the outside and which are connected by means of at least one upper and lower cross member, and having seat fittings which swivellably connect the backrest frame and the seat frame with one another and which each have a backrest-side fitting part and a seat-side fitting part.
In the case of a known vehicle seat of this type (German Patent Document DE 40 20 057 A1), the backrest side members, which are open toward the side, are provided in the interior with approximately zigzagging reinforcing ribs and cast-on threaded sleeves into which connected bolts can be screwed which penetrate the backrest-side fitting part as well as an inserted beaded relief plate and are used for fastening the backrest-side fitting parts to the backrest side members. In addition, a backrest supporting structure is known (German Patent Document DE 38 41 532 A1) which consists of a plastic injection-molded part and has backrest side members which are open to the side, the hollow space situated in the latter being provided with ribs used for the reinforcement and being coverable by means of an exterior covering.
In the case of another known vehicle seat (German Patent Document DE 42 38 549 A1), the backrest side members are constructed as open profiles which are cast in a thin-walled manner and which are connected along their length in one piece with one support york respectively. The backrest-side fitting parts of the seat fittings are rivetted laterally from the outside to the backrest side members, while the seat-side fitting parts have bores for the leading-through of fastening screws.
Normally, operating parts are attached to such vehicle seats, such as a motor-operated backrest adjuster for the swivelling of the backrest frame with respect to the seat frame or a seat belt system. Special fastening constructions must then be provided on the backrest frame for this purpose.
It is an object of the invention to provide a vehicle seat of the initially mentioned type which, in the manner of a building block system, can be upgraded by means of standardized supplemental parts from a simple seat for the lower priced vehicle models to an integral seat for the highest priced vehicle models, with a clear advantage with respect to manufacturing costs.
This object is achieved according to the invention by providing a vehicle seat of the above-noted type, wherein each backrest side member has a surrounding edge profile which projects in one piece from a profile surface to the outside and on which, at least in a lower area close to the seat frame, fastening elements are arranged for the common fastening of a backrest-side fitting part of the seat fittings and of a reinforcement or of a module which carries at least one operating part, such as a backrest adjusting drive, a seat belt system, a side bag, or an armrest, and wherein the backrest-side fitting part of the seat fittings and the reinforcement or the module are accommodated in the edge profile in a form-locking manner at least in the fastening area.
The vehicle seat according to the invention has the advantage that it can be upgraded by means of a standardized, stable basic backrest from a basic seat model of the simplest construction to a comfort model with a belt retractor, a side bag, a side impact protection, an armrest, a motor-operated backrest adjusting device or other operating parts integrated according to the customer's wishes. By means of the given modules, the vehicle seat can therefore be adapted to a plurality of very different demands, without the requirement of always having to manufacture new tools for the complete seat. The most expensive part of the vehicle seat, specifically the largely crash-resistant backrest frame as well as the seat frame with the displacing mechanism, are the same for all seats so that the manufacturing costs can be lowered as the result of the number of manufactured pieces (piece number effect).
Advantageous embodiments of the vehicle seat according to the invention with expedient further developments and embodiments of the invention are described herein and in the claims.
According to a first embodiment of the invention, in the simplest case of a vehicle seat design, only one motor-operated backrest adjusting mechanism is provided as an operating part which is mounted on the backrest-side fitting part of the seat fitting which acts as the support.
In a preferred embodiment of the invention, the module is constructed such that, after the fastening to the backrest side member, it forms a closed member profile together with it. As a result, the open profile of the backrest side members is converted by means of the module, which may be made of a cast material, sheet metal or a plastic material, to a closed profile with a clearly higher stability so that the module can also be used for the adaption of the backrest frame to almost any cases of stress.
According to a further embodiment of the invention, the module, which is placed on the exterior backrest side member (facing the vehicle side wall when the vehicle seat is installed into the vehicle), is also equipped with a seatbelt. The belt retractor and the upper deflection fitting of the safety belt system are integrated in the module and the lower end fitting of the safety belt is arranged on the seat-side fitting part of the seat fitting.
In further developments of the invention, a side bag can also be integrated in this module support. Also a laterally projecting support for a headrest can be fastened or molded to this module support.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.